Temporal correlation between the optical and γ-ray flux variations in the blazar 3C 454.3
Abstract
Blazars show optical and γ-ray flux variations that are generally correlated, although there are exceptions. Here we present anomalous behaviour seen in the blazar 3C 454.3 based on an analysis of quasi-simultaneous data at optical, ultraviolet, X-ray, and γ-ray energies, spanning about 9 yr from 2008 August to 2017 February. We have identified four time intervals (epochs), A, B, D, and E, when the source showed large-amplitude optical flares. In epochs A and B the optical and γ-ray flares are correlated, while in D and E corresponding flares in γ-rays are weak or absent. In epoch B the degree of optical polarization strongly correlates with changes in optical flux during a short-duration optical flare superimposed on one of long duration. In epoch E the optical flux and degree of polarization are anticorrelated during both the rising and declining phases of the optical flare. We carried out broad-band spectral energy distribution (SED) modelling of the source for the flaring epochs A,B, D, and E, and a quiescent epoch, C. Our SED modelling indicates that optical flares with absent or weak corresponding γ-ray flares in epochs D and E could arise from changes in a combination of parameters, such as the bulk Lorentz factor, magnetic field, and electron energy density, or be due to changes in the location of the γ-ray-emitting regions.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2019
- DOI:
- 10.1093/mnras/stz941
- arXiv:
- arXiv:1903.12637
- Bibcode:
- 2019MNRAS.486.1781R
- Keywords:
-
- galaxies: active;
- galaxies: jets;
- galaxies: nuclei;
- quasars: individual: 3C 454.3;
- gamma-rays: galaxies;
- X-rays: galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- accepted in mnras, 17 pages, 31 figures